There may be no single cause of bipolar disorder (aka manic depression). Instead, research indicates the causes of bipolar disorder are probably a combination of biochemical, genetic and environmental factors that may trigger and perpetuate the chemical imbalances in the brain.
Net worth: $829 million. Telecommunications mogul Strive Masiyiwa is widely regarded as the richest man in Zimbabwe and is one of the richest men in Africa with a net worth of more than US$800 million.
Harare is the capital city of Zimbabwe in southern Africa. Harare is Zimbabwe's biggest city with a population of around 2 million; it's also the commercial capital of the country. The British founded the city in 1890 and called it Salisbury.